Quantum frequency standards are the devices for exact measuring of frequency oscillating, based on the frequency calculating of quantum transition (in super high frequency and optical spectrum) of atoms ions or molecules from one condition to another. In passive quantum frequency standards they used the frequencies of the absorption spectral line and in active quantum frequency standards they used the particles emitted photons. They are known: active quantum frequency standards on the ammonia molecules beams (molecular generator) on the hydrogen generator (hydrogen generator) passive quantum frequency standards on the Cs atomsí beam (cerium atomic beam tube); active and passive quantum frequency standards with an optical pumping of Cs or Rb steams. The stability of atomic beam quantum frequency standard achieves 10^ - 14. Quantum frequency standards are used in navigation and time service as frequency (time) standards.